Installing Kubernetes on AWS with kops

Installing Kubernetes on AWS with kops

Overview

This quickstart shows you how to easily install a Kubernetes cluster on AWS. It uses a tool called 

kops

.kops is an opinionated provisioning system:Fully automated installation
Uses DNS to identify clusters
Self-healing: everything runs in Auto-Scaling Groups
Limited OS support (Debian preferred, Ubuntu 16.04 supported, early support for CentOS & RHEL)
High-Availability support
Can directly provision, or generate terraform manifests
If your opinions differ from these you may prefer to build your own cluster using kubeadm as a building block. kops builds on the kubeadm work.

Creating a cluster

(1/5) Install kops

Requirements

You must have kubectl installed in order for kops to work.

Installation

Download kops from the releases page (it is also easy to build from source):On MacOS:

wget https://github.com/kubernetes/kops/releases/download/1.8.0/kops-darwin-amd64 chmod +x kops-darwin-amd64
mv kops-darwin-amd64 /usr/local/bin/kops
# you can also install using Homebrew
brew update && brew install kops

On Linux:

wget https://github.com/kubernetes/kops/releases/download/1.8.0/kops-linux-amd64 chmod +x kops-linux-amd64
mv kops-linux-amd64 /usr/local/bin/kops

(2/5) Create a route53 domain for your cluster

kops uses DNS for discovery, both inside the cluster and so that you can reach the kubernetes API server from clients.kops has a strong opinion on the cluster name: it should be a valid DNS name. By doing so you will no longer get your clusters confused, you can share clusters with your colleagues unambiguously, and you can reach them without relying on remembering an IP address.You can, and probably should, use subdomains to divide your clusters. As our example we will use 

useast1.dev.example.com

. The API server endpoint will then be 

api.useast1.dev.example.com

.A Route53 hosted zone can serve subdomains. Your hosted zone could be 

useast1.dev.example.com

, but also 

dev.example.com

 or even 

example.com

. kops works with any of these, so typically you choose for organization reasons (e.g. you are allowed to create records under 

dev.example.com

, but not under 

example.com

).Let’s assume you’re using 

dev.example.com

 as your hosted zone. You create that hosted zone using the normal process, or with a command such as 

aws route53 create-hosted-zone --name dev.example.com --caller-reference 1

.You must then set up your NS records in the parent domain, so that records in the domain will resolve. Here, you would create NS records in 

example.com

 for 

dev

. If it is a root domain name you would configure the NS records at your domain registrar (e.g. 

example.com

 would need to be configured where you bought 

example.com

).This step is easy to mess up (it is the #1 cause of problems!) You can double-check that your cluster is configured correctly if you have the dig tool by running:

dig NS dev.example.com

You should see the 4 NS records that Route53 assigned your hosted zone.

(3/5) Create an S3 bucket to store your clusters state

kops lets you manage your clusters even after installation. To do this, it must keep track of the clusters that you have created, along with their configuration, the keys they are using etc. This information is stored in an S3 bucket. S3 permissions are used to control access to the bucket.Multiple clusters can use the same S3 bucket, and you can share an S3 bucket between your colleagues that administer the same clusters - this is much easier than passing around kubecfg files. But anyone with access to the S3 bucket will have administrative access to all your clusters, so you don’t want to share it beyond the operations team.So typically you have one S3 bucket for each ops team (and often the name will correspond to the name of the hosted zone above!)In our example, we chose 

dev.example.com

 as our hosted zone, so let’s pick 

clusters.dev.example.com

 as the S3 bucket name.Export 

AWS_PROFILE

 (if you need to select a profile for the AWS CLI to work)
Create the S3 bucket using 

aws s3 mb s3://clusters.dev.example.com

You can 

export KOPS_STATE_STORE=s3://clusters.dev.example.com

 and then kops will use this location by default. We suggest putting this in your bash profile or similar.

(4/5) Build your cluster configuration

Run “kops create cluster” to create your cluster configuration:

kops create cluster --zones=us-east-1c useast1.dev.example.com

kops will create the configuration for your cluster. Note that it only creates the configuration, it does not actually create the cloud resources - you’ll do that in the next step with a 

kops update cluster

. This give you an opportunity to review the configuration or change it.It prints commands you can use to explore further:List your clusters with: 

kops get cluster

Edit this cluster with: 

kops edit cluster useast1.dev.example.com

Edit your node instance group: 

kops edit ig --name=useast1.dev.example.com nodes

Edit your master instance group: 

kops edit ig --name=useast1.dev.example.com master-us-east-1c

If this is your first time using kops, do spend a few minutes to try those out! An instance group is a set of instances, which will be registered as kubernetes nodes. On AWS this is implemented via auto-scaling-groups. You can have several instance groups, for example if you wanted nodes that are a mix of spot and on-demand instances, or GPU and non-GPU instances.

(5/5) Create the cluster in AWS

Run “kops update cluster” to create your cluster in AWS:

kops update cluster useast1.dev.example.com --yes

That takes a few seconds to run, but then your cluster will likely take a few minutes to actually be ready. 

kops update cluster

 will be the tool you’ll use whenever you change the configuration of your cluster; it applies the changes you have made to the configuration to your cluster - reconfiguring AWS or kubernetes as needed.For example, after you 

kops edit ig nodes

, then 

kops update cluster --yes

 to apply your configuration, and sometimes you will also have to 

kops rolling-update cluster

 to roll out the configuration immediately.Without 

--yes

, 

kops update cluster

 will show you a preview of what it is going to do. This is handy for production clusters!

Explore other add-ons

See the list of add-ons to explore other add-ons, including tools for logging, monitoring, network policy, visualization & control of your Kubernetes cluster.

What’s next

Learn more about Kubernetes concepts and 

kubectl

.
Learn about 

kops

 advanced usage

Cleanup

To delete you cluster: 

kops delete cluster useast1.dev.example.com --yes

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